Riyadh, Feb 19 (AP) Top US and Russian officials had their most extensive high-level engagement since Moscow sent troops into Ukraine almost three years ago, meeting for nearly four hours on Tuesday in Saudi Arabia as President Donald Trump sought to advance his goal of ending the fighting in Ukraine and mending ties with Moscow.

The delegations led by US Secretary of State Marco Rubio and Russian Foreign Minister Sergey Lavrov said the discussions were a good first step.

They agreed to set up teams to look into restoring staffing at the US and Russian embassies in Moscow and Washington that have been decimated by a series of tit-for-tat diplomatic expulsions. The effort is aimed at using those channels to support Ukraine peace negotiations and to explore ways to restart economic and global cooperation.

However, the rapprochement may come at a cost to the transatlantic alliance of the US and Europe and significantly damage Washington's standing with Ukraine as well as with other nations counting on US leadership in NATO and elsewhere for their security and protection.

During former President Joe Biden's administration, the US and Europe focused on isolating Russia and defending the post-World War II international order.

First on both countries' list of accomplishments was an agreement to end what has been years of dwindling diplomatic relations that hit a post-Cold War low point after Russian President Vladimir Putin sent troops into Ukraine in February 2022.

The meeting, which came just a week after Trump spoke to Putin by phone, was the first substantive face-to-face discussion between the nations' top diplomats since former Secretary of State Antony Blinken met Lavrov in Geneva in January 2022 in an unsuccessful bid to prevent the Ukraine conflict.

Lavrov said after Tuesday's talks that the sides agreed to fast-track the appointment of new ambassadors, adding that senior diplomats from the two countries will meet shortly to discuss specifics related to "lifting artificial barriers to the work of the US and Russian embassies and other missions".

In reality, the decimation of the US and Russian embassies personnel began after 2014 Russia's annexation of Crimea that was seen as illegal by most of the world during the Obama administration, which ordered several Russian offices in the US to close.

It picked up steam after the 2018 poisoning in the UK of an exiled Russian spy and his daughter, and resulted in mass expulsions of diplomats and the closure of numerous consulates in both countries and Europe.

Asked by AP if the US now considered those cases closed, Rubio declined to say but said it would be impossible to get a Ukraine peace agreement without diplomatic engagement.

"I'm not going to negotiate or talk through every element of the disruptions that exist or have existed in our diplomatic relations, on the mechanics of it," he said.

The two sides agreed to set up high-level working groups to begin exploring a negotiated end to the conflict.

As to concessions that may need to be made by all sides, Trump's national security advisor, Mike Waltz, who participated in the talks, said the issue of territory and security guarantees would be among the subjects discussed.

Rubio said a high-level team, including experts who know technical details, will begin to engage with the Russian side on "parameters of what an end to this conflict would look like".

On the key issue of a prospective peacekeeping mission to monitor a potential ceasefire in Ukraine, the top Russian diplomat said Moscow would not accept any troops from NATO members, repeating its assertion that Ukraine's bid to join the Western military alliance poses a major security issue.

Neither Ukraine nor European nations were invited to Tuesday's talks in Riyadh but US officials said there is no intention to exclude them from peace negotiations should they begin in earnest.

Rubio said, "Obviously, there's going to be engagement and consultation with Ukraine, with our partners in Europe and others. But ultimately, the Russian side will be indispensable to this effort." Waltz agreed, "If you're going to bring both sides together, you have to talk to both sides... " He noted that Trump spoke with Ukrainian President Volodymyr Zelenskyy immediately after speaking with Putin last week and that US Vice-President JD Vance and Rubio met with Zelenskyy in Germany.

Zelenskyy postponed plans to visit Saudi Arabia on Wednesday to avoid any linkage of his trip with Tuesday's US-Russia talks.

"This whole negotiation from the start seems very tilted in Russia's favour. And it's even a question whether it should be termed a negotiation or in some sense, a series of American capitulations," said Nigel Gould-Davies, senior fellow for Eurasia and Russia at the International Institute for Strategic Studies in London and a former British ambassador to Belarus.

Immediately after the talks, Rubio briefed the foreign ministers of France, Germany, Italy and the UK and the EU's high representative for foreign affairs.

Asked whether the US could lift sanctions against Moscow imposed during the Biden presidency, Rubio noted that "to bring an end to any conflict, there has to be concessions made by all sides" and "we're not going to predetermine what those are".

Kirill Dmitriev, head of the Russian Direct Investment Fund who joined the Russian delegation in Riyadh, told reporters that Russia and the US should develop joint energy ventures. (AP) SZM